Such washer nozzles are often used in screen wash systems of modern motor vehicles and are known in practice for cleaning windscreens, rear windows or headlamp lenses. The washer nozzle generates a jet of washing fluid depending on the shape of the jet insert. The check valve prevents the washing fluid from running back when the screen wash system is at rest. Such a back flow would lead to greatly delayed response of the screen wash system on restart.
A washer nozzle is known in practice in which a check valve is arranged directly behind the connection of the housing. For this, the check valve has a catch connection and a seal in the connection. The disadvantage with this washer nozzle is that it is very complex to construct and install.